Question

Suppose that y varies inversely with x. Given x=-3 when y=-105. Find y when x is 15

Answer 1

The value of y is 21.

Explanation:

The formula of inversely proportional is y = k/x where k is a constant. So in order to find y, you first have to find the value of k by substituing x and y values into the formula :

`y = (k)/(x)`

Let y = -105,

Let x = -3,

`- 105 = (k)/( - 3)`

`k = - 105 * - 3`

`k = 315`

We have already found k value. Next you have to find the value of y :

`y = (315)/(x)`

Let x = 15,

`y = (315)/(15)`

`y = 21`